Re: Concertlina II: Full Circle

John Savard wrote:

On Mon, 17 Jun 2024 20:20:03 +0000, mitchalsup@aol.com (MitchAlsup1)
wrote:

As to looping, I faced the same delimma and came to a different
conclusion::
You don't do it in 1 instruction, instead, you do it in a way where
your
2 instruction encoding executes one of the instructions only once. I
call
this bookending the loop.

I considered something like that.

My problem was that encoding the parameters of the loop in one
instruction takes too much space. So the first thing I thought of was
to put some of them in the instruction that repeats the loop.

The proiblem was, though, that since the instruction that repeats the
loop points to the start of the loop in memory, it's a
memory-reference instruction, so there isn't much extra room left in
it.

No, it is not a memref--it is a return ! using the register from the VEC  instruction. You "return" to the top of the loop. There is no reason to use IP+Disp, and the fact there is no register nor disp-
lacement in LOOP enables it all to fit. In addition, when VEC executes,
IP is pointing at the top of the loop, requiring no calculation whatsoever.

However, there is a little room left, so I may indeed go back and
explore that possibility some more.

John Savard